Grasslands comprise natural tropical savannah over managed temperate fields to tundra and cover over a quarter of the Earth's land surface. Plant growth, maintenance and decay result in volatile organic compound (VOCs) emissions to the atmosphere. Furthermore, biogenic VOCs (BVOCs) are emitted due to various environmental stresses including cutting and drying during harvesting. Fluxes of BVOCs were measured with a proton-transfer-reaction – mass-spectrometer (PTR-MS) over temperate mountain grassland in Stubai Valley (Tyrol, Austria) over one growing season (2008). VOC fluxes were calculated from the disjunct PTR-MS data using the virtual disjunct eddy covariance method and the gap filling method. The two independent methods obtained methanol fluxes following a regression line of y=0.94x−0.06 (correlation factor: R2=0.94). Methanol showed strong daytime emissions throughout the growing season. With maximal values of 9.7 nmol m−2 s−1 the methanol fluxes from growing grassland were considerably higher at the beginning of the growing season in June compared to those measured during October (2.5 nmol m−2 s−1). During the growth only methanol emissions were observed. The cutting and drying of the grass increased the emissions of methanol, up to 30 nmol m−2 s−2. In addition, emissions of acetaldehyde, up to 10 nmol m−2 s−1, and hexenal (leaf aldehyde) were detected during harvesting.